\documentclass[12pt]{article}

\usepackage{graphicx}
\usepackage{booktabs}
\usepackage{amsmath}
\usepackage{caption}
\usepackage{nopageno}
\usepackage{longtable}
\usepackage{lscape}
\usepackage{setspace}
\usepackage[margin = 1in]{geometry}

\title{Appendix Extensive Margin Tables}
\author{}

\addtolength{\tabcolsep}{2pt}

\begin{document}

% Table A3
\begin{landscape}
\setlength{\tabcolsep}{9pt}
\input{boughtdur2_tabs}
\end{landscape}

\clearpage

% Table A4
\begin{landscape}
\setlength{\tabcolsep}{9pt}
\input{boughtdur2_morttabs}
\end{landscape}

\end{document}